<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>模拟数据监测</title>
  </head>
  <body>
    <script>
      let data = {
        name: "尚硅谷",
        address: "北京",
      };

      //创建一个监视对象 用于监视data中属性的变化
      const obs = new Observer(data);
      console.log(obs);

      //准备一个vm实例对象
      let vm = {};
      vm._data = data = obs;

      function Observer(obj) {
        //汇总对象中所有的属性 形成一个数组
        const keys = Object.keys(obj);
        //遍历
        keys.forEach((k) => {
          Object.defineProperty(this, k, {
            get() {
              return obj[k];
            },
            set(val) {
              console.log(
                `${k}被改了，我要去解析模板，生成虚拟DOM，...我要开始忙了`
              );
              obj[k] = val;
            },
          });
        });
      }
    </script>
  </body>
</html>
